how to tab on an iPad

The presence of the keyboard <Tab> key will be determined by your iPad model. The native iPad on-screen keyboard may only be available on iPad Pro 11” and 12.9” models.

While the native on-screen keyboard for your iPad may not include a <Tab> key, there are third-party keyboard Apps that will provide access to additional keys. A popular alternative is Typefinity:

https://apps.apple.com/gb/app/typefinity/id1512009869

The Notes App does not support creation of tabs. You can, however, have two Notes open using iPadOS split-screen or slide-over multitasking views - or three if both types of view are used at the same time.

More information about using multi-tasking can be found in this support page:

Use multitasking on your iPad - Apple Support

The iPad User Guide is also a rich source of information about using iPad and its many features. The Guide is available both online using a web browser (such as Safari), or as an Apple Books download:

iPad User Guide - Apple Support

https://books.apple.com/book/id1567104892

I assume that you mean creating tabs and if so, that would be an option in the app in which you want to create tabs. Care to share which app you are talking about?

Do you mean inserting a tab character ie the equivalent of 4 spaces?